Method for automatically adjusting a drawer conveyor in accordance with the size of articles to be transported, and conveyor that carries out the method

Abstract: A method for automatically adjusting a drawer conveyor in accordance with the size of articles to be transported, the conveyor (1) running along a closed loop path and including transporting drawers (2) comprising a pair of walls (20,22) which define the dimension of the drawers. The method includes releasing one of the walls in a first section of the conveyor path, moving the released wall (22) in a second section of the conveyor path, until it is positioned at a pre-set distance from the other one, and locking again the previously released wall in a third section of the conveyor path. The conveyor includes an adjusting operating station located along the path designed to carry out subsequently on each drawer (2) that passes near to it, the operations described above.

Description: The present invention concerns a method for automatically adjusting a drawer conveyor in accordance with the size of articles to be transported. The conveyor which the method refers to, runs along a closed loop path and is equipped with conveying drawers comprising a pair of walls which define the dimension of the drawers. Currently, automatic packaging machines that insert products into cases, generally include three closed loop conveyors, placed side by side with their upper runs substantially coplanar. The first conveyor is equipped with stopping means for positioning of erected preformed cases thereon, the erected cases having at least an open side facing the second conveyor. This second conveyor is equipped with drawers for products which are lined up with the cases carried by the first conveyor while the third conveyor is equipped with pusher means operated transversely while they move along the upper run of the packaging line, so that the pushing means moves the products carried by the second conveyor towards the respective cases on the first conveyor, thus inserting them therein. The drawers comprises lateral walls arranged transversely in respect to the transport direction, and are fed with product at the side opposite to the side facing the case carrying conveyor. The basic problem of the drawer conveyors concerns the possibility of adjustment of the drawers in accordance with the size of the products to be conveyed, that means to change the dimension of the drawers accordingly. For this purpose some conveyors have at least one of the side walls making up the drawers that is made movable in respect to the other that is fixed to the drawer support body, and the translation of said movable drawer is provided by different systems. For example, notches may be made in the drawer support body and may be spaced apart in the transport direction, the notches being designed to receive in engagement the movable walls that can be set in the most suitable position. This system, however, requires considerable costs and work and the machine being stopped at every adjustment. In accordance with a second system, that is described in the Italian Patent Application No.RM91A000091, the movable wall can be shifted to the suitable position, while the conveyor is in operation, by means acting along the advancement direction in a continuous way and coacting with translating means carried by the drawer body and linked to the movable wall. According to a third system, a plurality of housings are defined by couples of prongs respectively located on the two longitudinal sides of the conveyor and made integral with two sets of chains, each one including include two or more chains. Each couple of prongs are set at a distance from the following couple equal to the product width. All the chains are moved with the same speed, while one set of chain can be shifted in respect of the other in order to adjust the conveyor in accordance with the product size, so as to obtain the desired longitudinal distance between the pairs of prongs belonging to the respective sets of chains. On one side, this arrangement allows to obtain the adjustment with a minimal number of phases, on the other side, however, it implies constructive complications and subsequent realisation and maintenance costs. Moreover, such a solution brings about functional problems, since it is the product that is transversally pushed toward the relative package thus making it possible for the product to strike the edge of the open side of the package. In case of a drawer conveyor, each drawer translates transversally toward the relative package, partially inserts therein through open side, and consequently, the drawer's entering into the package facilitates subsequent product introduction into the package. The document DE-A-3815557 discloses a drawer conveyor with one wall of each drawer carried by two chains and the other wall of the same drawer carried by two further chains placed bilaterally to the precedent ones. During operation the four chains are driven with the same speed: in this way the same distance between the walls of various drawers is maintained. In order to change the drawer dimension, the chains relative to one wall are shifted in respect to the others until the desired dimension is obtained for the drawers. Such a solution provokes not only constructive and space complications, but also a disadvantage resulting from the fact that possible anomalies, e.g. caused by chains lengthenings, affect all the drawers. Therefore, the object of the present invention is to avoid the above reported disadvantages by proposing a method for automatically adjust a drawer conveyor in accordance with the size of the article to be transported, the conveyor running along a closed loop path and being equipped with transporting drawers, each comprising a pair of walls. The method is characterised by the fact that it includes the following phases: releasing one wall while the drawer is running a first section of the conveyor path; shifting the above mentioned wall while the drawer is running a second section of the same path, until the wall is set at a pre-determined distance from the other wall; locking again the wall previously released, when the drawer is in a third section of the conveyor path. An embodiment of said method is characterised by the fact that an adjustment station works for a period of time necessary for all the drawers to pass through it, that is, in case of a single station, for a time necessary to complete a full turn of said closed loop. Another object of the present invention is to provide a conveyor that can be automatically adjusted in accordance with the size of the product to be transported. This conveyors runs along a closed loop path and is equipped with convey drawers comprising a pair of walls. The above mentioned objects are achieved by means of a conveyor as described in claim 3. Further preferred characteristics and advantages of the present invention will result from the following detailed description of its preferred embodiment, that is described as a mere example not limitative, with reference to the enclosed figures, in which: Figure 1 is a plan view of the drawer conveyor during the adjustment phase; Figure 2 is a plan view of the drawer conveyor during operation; Figure 3 is a plan view of an adjustment station; Figure 4a is a section view along the IV-IV line of the Figure 3 with the conveyor in operation; Figure 4b is a section view along the IV-IV line of the Figure while the conveyor is in the adjustment phase; Figure 5 is a section view along the V-V line of Figure 4a; Figure 6 is a section view along the VI-VI line of the Figure 4a; Figure 7 is a schematic plan view of the adjustment station in the operative phase; Figures 8a and 8b are two constructive particulars of the guides of the drawer body in the views frontal and back to the conveying direction. With reference to Figure 2, numeral 1 indicates a drawer conveyor, each drawer 2 of which consists of a first stationary element 18 and a second element 21. The elements 18 and 21 are placed longitudinally to the conveying direction and they define a housing 5 designed to receive the product 6 loaded by known loading means, not illustrated. The products 6, hold in that manner, are conveyed along the packaging line up to the station S2 in which the drawers 2 of said conveyor 1 come up by the side of another conveyor 7. Generally, the conveyor 7 has holding elements for placing thereon preformed erected cases 8, and for conveying them along the packaging line with at least one open side facing the conveyor 1. At a station S2, the products 6 while being advanced are also translated inside the cases 8 by generic pushing means indicated with 9, to obtain packages 10. With reference to the figures 3, 4a and 5, the drawer conveyor 1 includes a pair of chains 11 parallel to the packaging line and carrying cross bars 12 that engage and support slidingly a convey block 13 so as to advance it along the packaging line. At its lower end, the convey block 13, carries a pivoted idle cam following roller 14 designed to engage with a cam 15. The cam 15 locates the convey block 13 by moving it transversally, and at the station S2 the cam brings the convey block to come alongside the packages conveyor 7 so that the drawers 2 are partially inserted into the respective cases 8, through the open side of the latters. Near to its top, said convey block 13, carries a drawer support body 17 that comprises the first "L"-like element 18, bound to said convey block 13, and the second "L"-like element 21, slidingly guided in direction normal to the first element 18. The first element 18 includes a bottom wall 19 of the drawer body 17, that is fixed to the convey block 13, and a first stationary wall 20. The second element 21 includes a second wall 22 and a plan 23 that is slidingly resting on the upper surface of the bottom wall 19 of the drawer body 17. With reference to Figures 8a and 8b, showing the guide means which connect the elements 18 to the element 21, the plan element 23, joint to the second wall 22, has its bottom fixed to a sliding guide element 25, shaped like an upturned "T". The element 25 slides freely in a slot 24 made in the bottom wall 19 (see Fig. 3). The element 25 is a rack element that adheres and slides very near to the lower plane of the bottom wall 19, and extends transversally to the walls 20 and 22 until it fits into an opening 26 made in the convey block 13 (see Fig. 8b). The plane 23 and the rack sliding element 25 are fixed one to another and they carry a pivot 27 that pass through a slot 65 made at the end of an angular lever 28 pivoted in 29 on the bottom wall 19 of the drawer body 17. The other end of the lever 28 carries a roller 32 that, when it is shifted, causes the second wall 22 to move while remaining parallel to the stationary wall 20 of the drawer body 17. In this way, translation means for the second wall are defined. With reference to Figures 4a and 4b, the convey block 13 carries locking means which include a rocker lever 34 pivoted in 33, the upper end of which carries a toothed sector 35 designed to be positioned in engagement with or disengagement from the teeth of the rack 25. When the toothed sector 35 is pushed on the rack 25, the second wall 22 is locked to the drawer body 17 and to the convey block 13. The lower part of the lever 34 carries a reset spring 36 and a pivot 37 carrying a roller 38. When the roller is shifted, in the way that is better explained in the following, the toothed sector 35 is disengaged from the rack 25, and the wall 22 is released from the drawer body 17 and to the convey block 13. Still with reference to the figures 3, 4a, 4b and 6, the conveyor structure 39 has fixed thereto a support block 42 that in its upper part carries a shifting plate 43. The plate 43 slides transversally to the conveying direction by means of prismatic coupling guides (See in particular Fig. 6) and positioning means. In fact, its end opposite to the conveyor 1, the positioning plate 43, is in screwed engagement with a threaded bar 44 that is keyed on a handwheel 45 rotatably mounted rotatably on the conveyor structure 39. In that manner, a coupling is obtained in which, by the rotations of the handwheel 45, the plate 43 moves transversally to the conveying direction. In its upper part, the plate 43, carries a plate 40 pivoted by a pivot 41. The surface of the plate 40 facing the conveyor 1 has made therein a funnel-like groove 46 which forms shifting means, or cam tracks 47, 48, designed to engage the roller 32 of the angle lever 28. Linking means between the positioning means and the shifting means are now described. Inside the support block 42, there is made a notch 49, in which the head 50 of a bolt 51 is inserted slidingly so that it cannot rotate. The bolt shaft 52 extends upwards passing through the walls 53 of a cylindrical hole made in the plate 43, until it screws into the shaft 54 of a clamping 55 handwheel. The free end of the shaft 54 of said clamping hand-wheel 55 is in form of a cone 56 and engages reciprocally with a conical hole 57 made in the plate 40 in such a way that, acting on the handwheel 55, it is possible to obtain a coupling, between the plates 40 and 43, with (see Fig. 4b) or without clearance (see Fig. 4a). Thanks to the pivot between the plates 40 and 43, to the pivot 41, and to the conical coupling of the cone 56 with the conical hole 57, said plate 40 can oscillate, as indicated in Fig. 4b, adapting conical coupling with clearance or a non-oscillating coupling, as indicated in Fig. 4a, adopting a conical clamped coupling. In its lower part, the support block 42 carries a sliding prismatic bar 58, placed transversally to the conveying direction. The free end of said bar 58, placed at the side of the conveyor, carries a plate 59 with a cam profile 60 designed to cooperate with the roller 38 of the locking means. The other end of said bar 58 carries a pivot 61, on which a roller 62 is rotatably mounted, said roller 62 being engaged in a path 64 of a drum cam 63, mounted on a shaft 165 rotatably supported by the same support block 42 and keyed on a lever hub 66 for its rotation. Acting on the lever 66, the plate 59 proceeds or withdraws transversally to the conveying direction, entering in striking trajectory with the roller 38 or leaving the striking trajectory. In the above described drawer conveyor, the automatic adjustment requires an adjustment station S1 placed along a section of the conveyor path and that can be enabled or disabled. An way of carrying out the adjustment operation is now described as a mere example, not limitative. When the drawer conveyor is standstill or in movement, the plate 59 is moved forward, in the drawer conveyor 1 direction, by turning the shaft 165 by means of the lever 66, in such a manner that the cam-shaped profile 60 of the plate 58 be located along a path directed to strike the rollers 38 of the locking means associated to the related support blocks 13, thus defining three operating sections for the said rollers 38 (see Figure 7). With this configuration the conveyor 1 goes on through one complete turn, so that all drawers pass through the cited station 1 and undergoes therein the following actions: the roller 38 strikes the first raising section of the cam profile 60, so that the rocker 34 swings from a first position, that causes the wall 22 to be locked to the stationary wall 20, to a second position wherein the wall 22 is released and free to move with respect to the stationary wall 20; the second section of the cam profile 60 keeps on acting on the roller 38, so that the wall 22 remains in a released condition, while the roller 32 engages the funnel-like groove 46 so that the wall 22 is set at a pre-determined distance from the stationary wall 20 by means of the lever translating means 28; lastly, the third section of the cam profile 60 progressively releases the rocker 34 that, because of the action of the spring 36, swings back to the originary position, wherein the wall 22 results to be locked, and is thus well adjusted for the new article size. When the turn of the conveyor has been completed all the drawers have passed through the adjustment station S1 and consequently all of them have been adjusted to suit the new article size. At this point, by acting on the tightening wheel 55 the conical coupling 56-57 is disconnected, due to the clearance that results in the coupling, while by acting on the lever arm 66, the plate 59 is moved back, until it reaches its idle position (see Figure 4b). During operation of the conveyor, the rollers 38 do not strike the cam profile 60, since this last profile is in a retracted position. The plate 40 is free to swing about the pivot 41 and along an arch that is defined by the clearance set in the conical coupling 56-57, so that possible oscillations of the rollers 32 running in the grooves 46 and which are not perfectly lined up, have no effects. Furthermore, in order to avoid accidents, there is a sensor 67 located near to the lever arm 66, designed to detect the operating or idle condition of the plate 59. The most characterising feature of the present invention is that the wall 22 is made movable with respect to the stationary wall 22, that the wall 22 is kept in such mobile condition for a pre-set section of the conveyor 1 path, so as to allow the distance between the movable wall 22 and the stationary wall to be adjusted to suit a certain size of the articles, and finally to lock again the wall 22 with respect to the convey block 13. As an alternative to the above, the adjustment can be carried out by means of spacing plugs which are manually set into operation by an operator. The spacing plugs can be also somehow associated to the conveyor 1, for example by mounting them on a disc, or a drum, that is coaxially keyed to one of the wheel on which the chains of the conveyor 1 run. These spacing plugs should be placed between the walls 22 and 20 of the drawers, when the walls are located at the maximum distance from one another, at the beginning of the adjustment operation, and when the movable wall is moved nearer to the stationary wall 20, it is stopped by the plug, so that a predetermined distance between the two walls 20 and 22 is set and subsequently stabilised by the locking of the movable wall 22. Advantageously, the movable wall is moved against the elastic reaction of spring means, which allow to eliminate the effects of unavoidable clearances that exists among the means designed to move the movable wall. Thus dangerous mechanical stresses acting on the same moving means, due to anomalous situations which can occur while adjusting the size of the drawer, are avoided. As an alternative to the rack member 25 and to the connected toothed sector 35, any other mechanical means able to allow blocking of the movable member 25 to the convey block 13, can be used. For example a high friction material can replace the toothing on the rack member and the toothed sector. It must be stressed that what has been said above concerns every drawer so that a possible anomalous situation affecting the means designed to drive the drawer conveyor and/or the means designed to carry out the adjustment, do not have similar effects on all the drawers. It must be also highlighted that all what has been proposed can be applied to a drawer conveyor including a pair of chains, with all the advantages that this brings about with respect to the prior art described in the introductory statement.

Claims: Method for automatically adjusting a drawer conveyor in accordance with the size of the article (6) to be transported, said conveyor (1) running along a closed loop path and being equipped with conveying drawers (2), each comprising a pair of walls (20,22); the said method being characterised in that it includes the following phases: releasing a wall (22) of a drawer (2) while this drawer (2) is running along a first section of the said loop path: shifting this wall (22) while the drawer is running along a second section of the said path, until the movable wall is positioned at a pre-set distance from the stationary wall (20); locking again the wall (22) previously released, when the drawer (2) is running a third section of the same path. Method according to claim 1, characterised in that an adjusting operating station (S1) is activated to carry out the said phases, and operates for a time necessary to all the drawers (2) to pass through the same station (S1). Conveyor automatically adjusted in accordance with the size of the articles to be transported, the said conveyor (1) running along a closed loop path and being equipped with transporting drawers (2), each comprising a pair of walls (20,22), said conveyor including: conveying means comprising a first stationary wall (20) and a second wall (22), this second wall (22) being adapted to take either the one or the other of two different configurations, namely a first configuration in which the second wall (22) is locked, and a second configuration in which this second wall (22) is released and movable with respect to the said first stationary wall (20); operating means designed to release the said second wall (22) of a drawer (2) while this drawer (2) is running a first section of the said closed loop path, to keep the same wall (22) free while the drawer (2) is running a second section of the closed loop path, and then to lock the wall (22) previously released when the said drawer has reached a third section of the same path; positioning means for locating the said second wall (22) at a pre-set distance from the said first stationary wall (20) while said second wall is kept free. Conveyor according to claim 3, characterised in that the said transporting means further include: guiding means designed to slidingly guide said second wall (22) while moving nearer, to or farther, from said first stationary wall (20); locking means aimed at blocking the said second wall (22) with respect to the first stationary wall (20); and translating means designed to impose a translation to said second wall (22). Conveyor according to claim 4, characterised in that said guiding means include a pair of prismatic couplings positioned in a central position with respect of a drawer (2) and along a longitudinal direction of the same drawer, and including a sliding member (25) positioned beneath the bottom of the drawer (2), inside a groove made in the transporting means, said sliding member (25) having an end fixed to said second wall (22), thus defining a double "T" sliding along a slot (24) made in the bottom (19) of said drawer, transversally with respect of said walls. Conveyor according to claim 4, characterised in that said locking means include: a rack member (25) fixed to said second wall (22) and slidingly guided by the transporting means; a rocker member (34) that is pivoted to said transporting means and swings perpendicularly to said rack member, said rocker member having a toothed sector (35) fastened to an end thereof, this toothed sector being adapted to engage and disengage said rack member, while the other end of the said rocker member (34) has a cam-follower roller (38) designed to cooperate with said operating means for causing said second rocker member to swing; a re-setting spring (36) acting on said rocker member (34), said spring being designed to re-set said rocker member (34) to the position where it is in engagement with said rack member (25). Conveyor according to claim 4, characterised in that said translating means include an angle lever (28) positioned beneath the bottom of the drawer (2) and pivoted thereto, said angle lever (28) having an end hinged to said second wall (22) while the other end of said angle lever has a cam-follower roller (32) designed to cooperate with the said positioning means. Conveyor according to claim 3, characterised in that said operating means include: first shifting means, designed to cooperate with said transporting means, and which include a plate (59) movable along a direction that is transverse to the conveyor direction, with an edge of said plate facing said transporting means profiled to form a cam (60) and extending longitudinally to the transporting direction, so that said edge cooperates with said transporting means, said plate (59) also bearing a cam-follower roller (62) positioned near an edge of said plate opposite to the cam-profiled edge, this roller being designed to run inside a cam groove (64) made on a drum (63) rotatably supported by the conveyor structure and aimed at causing the sliding of said plate (59) transversally with respect to the transporting direction; second shifting means disposed in accordance with a longitudinal direction and movable along a direction transverse to said transporting direction; adjusting means designed to move said shifting means and to define a transverse position for the same shifting means; link means designed to connect said shifting means to said adjusting means with or without possibility of oscillation. Conveyor according to claim 8, characterised in the fact that said shifting means include a first shifting plate (43) with a funnel-like groove (46) parallel to the transporting direction and designed to engage a roller (32) of translating means of said second wall (22) supported by said transporting means. Conveyor according to claim 8, characterised in that said adjusting means include an adjusting wheel (45) rotatably mounted on the conveyor structure and supporting a threaded bar (44) keyed thereto and perpendicular to the transporting means, this threaded bar being in screw engagement with a second positioning plate (40). Conveyor according to claim 8, characterised in that said link means include a conical adjustable coupling comprising a conical member connected to said shifting means and another conical member connected to said adjusting means. Conveyor according to claim 3, characterised in that it includes sensor means cooperating with said operating means to detect the operation or non-operation state for these last operating means.

Inventors: MARTELLI GUGLIELMO, MARTELLI, GUGLIELMO
Applicants: AMRP HANDELS AG, A.M.R.P. HANDELS AG
Application year: 1994
Main classification: B65B59
IPC codes: B65G47, B65B59